The NRF IO of Ubox single
From Spintend service and support
Limit by it's size and design structure, the Ubox single doesn't provide a NRF port.
The NRF (Bluetooth) port is actually a UART port, assigned to the MCU's 51st and 52nd pin:
UART TX--------PC10 of MCU, pin 51
UART RX--------PC11 of MCU, pin 52
When connect these two IOs to NRF module, we also need to connect 5V and GND to NRF module.